Objective: We sought to study the diagnostic yield of increasing numbers of contrast injections for detection of patent foramen ovale (PFO) during transesophageal echocardiography.
Methods: Contrast was injected twice during each of 10 provocations to 30 patients screened for PFO. Injections were given during quiet respiration, early Valsalva (starting 3-5 seconds before injection), late Valsalva (starting 3-5 seconds after injection), Mueller maneuver, coughing, bed tilt during early Valsalva, after nitroglycerin spray during both quiet respiration, and early Valsalva.
Results: The number of detected PFOs increased as the number of injections increased (r = 0.79, P < .01). Five injections per patient detected all 11 large PFOs. To eventually detect all 14 PFOs among the 30 study patients required a total of 11 injections per patient.
Conclusion: The sensitivity for PFO detection increased when additional contrast injections were given. At least 5 injections are required to safely detect or rule out the presence of a PFO.